While oven heats, core bell peppers and halve them lengthwise. Coat outside of peppers lightly with olive oil. Place cut side down on baking sheet.

Cut zucchini into sticks and toss with olive oil, salt and pepper. Transfer to a baking sheet.

Grate cauliflower coarsely using a food processor or box grater.

Put zucchini and peppers into oven. Cook peppers for 10 minutes, then remove from oven and flip over once cooled slightly.

While zucchini and peppers cook, heat a drizzle of olive oil in a large frying pan or cast iron skillet over medium high heat. Add chopped onion and sautee for a few minutes until translucent. Add garlic and cook briefly.

Add ground beef to skillet and cook until browned, stirring occasionally. Season with salt and pepper. Add cauliflower and stir for a few minutes longer. Add mint, parsley and tomato sauce and cook briefly to evaporate any excess moisture.

Spoon beef and cauliflower filling into pepper halves. Return peppers to oven to cook for another 10 minutes.